BACKGROUND: Total colectomy with an ileorectal anastomosis (IRA) is a commonly performed operation. Postoperative mortality and morbidity are reported to be low and functional outcome is generally rated as good to excellent. The aim of this study was to review postoperative mortality, morbidity and functional results in an effort to identify risk factors predictive of a poor outcome. METHODS: Some 215 patients (118 women and 97 men) with a median age of 33 (interquartile range (i.q.r.) 25-47) years underwent an IRA between November 1990 and December 1999. Median follow-up was 2 years 9 months (i.q.r. 1-5 years). The clinical notes of these patients were reviewed retrospectively to analyse the postoperative course, bowel function and long-term clinical outcome. RESULTS: The indications for surgery included familial adenomatous polyposis (52.1 per cent), Crohn's disease (14.4 per cent), functional bowel disorder (14.4 per cent), ulcerative colitis (8.4 per cent) and colonic carcinoma (4.7 per cent). The overall 30-day mortality and morbidity rates were 0.9 and 26.0 per cent respectively. This included anastomotic leak (6.5 per cent), small bowel obstruction (14.4 per cent), fistula (2.8 per cent) and anastomotic stricture (1.4 per cent). The incidence of fistula and anastomotic stricture was significantly higher in Crohn's disease (P < 0.001 and P = 0.005 respectively). Only 16 of 31 patients with Crohn's disease had a functioning IRA at long-term follow-up. Median stool frequency was 3 (i.q.r. 3-5) per day one year following surgery and did not change with longer follow-up. CONCLUSION: Mortality and morbidity rates following IRA are low. Postoperative fistula and anastomotic stricture are more common in patients with Crohn's disease, approximately half of whom will eventually need a permanent ileostomy. Long-term bowel function for all groups is satisfactory.